Place CNAMEs first in each section.

driver.rkt

@@ -48,12 +48,12 @@
 		   'name-error
 		   'no-error)
 	       (dns-message-questions r1)
-	       (listset-union (dns-message-answers r1) (dns-message-answers r2))
-	       (listset-union (dns-message-authorities r1) (dns-message-authorities r2))
-	       (listset-union (dns-message-additional r1) (dns-message-additional r2))))
+	       (rr-listset-union (dns-message-answers r1) (dns-message-answers r2))
+	       (rr-listset-union (dns-message-authorities r1) (dns-message-authorities r2))
+	       (rr-listset-union (dns-message-additional r1) (dns-message-additional r2))))
 
-(define (listset-union xs1 xs2)
-  (set->list (set-union (list->set xs1) (list->set xs2))))
+(define (rr-listset-union xs1 xs2)
+  (rr-set->list (set-union (list->set xs1) (list->set xs2))))
 
 ;; start-server : UInt16 RR ListOf<RR> -> Void
 ;; Starts a server that will answer questions received on the given
@@ -121,9 +121,9 @@
 		   'no-recursion-available
 		   (if send-name-error? 'name-error 'no-error)
 		   (dns-message-questions request-message)
-		   (set->list answers)
-		   (set->list authorities)
-		   (set->list additional)))
+		   (rr-set->list answers)
+		   (rr-set->list authorities)
+		   (rr-set->list additional)))
 
     (define reply-packet
       (with-handlers ((exn? (lambda (e)

simplified-driver.rkt

@@ -92,9 +92,9 @@
 		 'no-recursion-available
 		 (if send-name-error? 'name-error 'no-error)
 		 (dns-message-questions request-message)
-		 (set->list answers)
-		 (set->list authorities)
-		 (set->list additional)))
+		 (rr-set->list answers)
+		 (rr-set->list authorities)
+		 (rr-set->list additional)))
 
   (define (answer-question q make-reply)
     ;; Notice that we claim to be authoritative for our configured

zonedb.rkt

@@ -14,6 +14,7 @@
 	 referral-for
 	 additional-section/a
 	 filter-rrs
+	 rr-set->list
 
 	 resolve)
 
@@ -105,6 +106,13 @@
       (else (set-filter (lambda (rr) (eqv? (rr-class rr) qclass)) filtered-by-type))))
   filtered-by-type-and-class)
 
+;; rr-set->list : SetOf<RR> -> ListOf<RR>
+;; Like set->list, but places all CNAME records first.
+;; This is apparently to work around bugs in old versions of BIND?
+(define (rr-set->list rrs)
+  (append (set->list (filter-by-type rrs 'cname))
+	  (set->list (set-filter (lambda (rr) (not (eqv? (rr-type rr) 'cname))) rrs))))
+
 ;; QuestionResult Maybe<QuestionResult> -> QuestionResult
 ;; Add the supporting facts from r2 into r1, keeping r1's
 ;; question. Replaces the knowledge from r1 with the knowledge from